Mary Geddes Stahlman Professor of Cancer Research; Professor of Biochemistry;Professor of Chemistry
Ph.D., Duke University, 1973
larry.marnett@vanderbilt.edu
Marnett Research Laboratory

Organic, Bioorganic and Biochemistry
Our research group has interests in the areas of protein structure and function, nucleic acid chemistry, drug design and synthesis, and chemical genomics. Much of our work focuses on the biochemistry and molecular biology of oxidation of natural and synthetic chemicals. Areas of interest to us include: mechanisms of oxidation of arachidonic acid and endocannabinoids by cyclooxygenase and lipoxygenase enzymes, design, synthesis, and biochemical evaluation of lipoxygenase and selective cyclooxygenase-2 (COX-2) inhibitors; chemistry and biology of DNA damage by lipid oxidation products; and endogenous pathways of DNA damage in the genesis of human cancer.

The following studies are underway in our labs:

Structure and Function of Fatty Acid Oxygenases
Our laboratory has a long-standing interest in enzymes of arachidonic acid oxygenation. This includes lipoxygenases, which incorporate one molecule of O₂ into the carbon framework and cyclooxygenases, which incorporate two molecules of O₂. The products of both pathways of oxygenation are substrates for metabolizing enzymes that generate a panoply of lipid mediators. Leukotrienes and prostaglandins are involved in multiple physiological and pathophysiological events, and inhibition of their action is the molecular basis for the pharmacological activities of several important drugs. Foremost among these are non-steroidal anti-inflammatory drugs (NSAIDs) and cyclooxygenase-2 (COX-2) inhibitors. We have conducted extensive functional studies with lipoxygenases and cyclooxygenases based on available crystal structures and employing exhaustive site-directed mutagenesis.

Design, Synthesis, and Evaluation of Novel COX-2 Inhibitors
Cyclooxygenase-2 (COX-2) is the molecular target of non-steroidal anti-inflammatory drugs (NSAIDs) and selective COX-2 inhibitors. Our laboratory has combined structural analysis with functional studies to define the molecular determinants of the interaction of ligands (substrates and inhibitors) with COX-2. For example, we recently reported the identification of a critical H-bonding interaction that leads to the selectivity of aspirin for acetylation of Ser-530 in COX-2. Many NSAIDs are aralkyl carboxylic acids. Comparative analysis of the effect of site-directed mutation of active site residues on the binding of substrates and inhibitors to COX-1 and COX-2 led us to hypothesize that neutral derivatives of esters and amides would bind selectively to COX-2. We tested this hypothesis by synthesizing a series of neutral derivatives of NSAIDs and demonstrating increases in selectivity for COX-2 of several orders of magnitude. We are exploiting this discovery to prepare novel COX-2 inhibitors as anti-inflammatory drugs and cancer preventive agents.

Chemistry and Biology of Endogenous DNA Damage by Lipid Peroxidation Products
Our laboratory has focused on DNA damage by aldehydes produced endogenously in mammalian cells as a result of lipid peroxidation. Malondialdehyde is the major mutagenic product of lipid peroxidation and is produced ubiquitously in animal and human tissues. It reacts with DNA to form a series of adducts that we and others have identified. The major adduct is a pyrimidopurinone that we have abbreviated M₁G. This adduct possesses a blocked Watson-Crick base-pairing region so it is expected to be mutagenic. We have evaluated its mutagenicity by synthesizing viral genomes containing M₁G at defined positions. Following transfection into bacterial or mammalian hosts, the replicated genome is interrogated to determine the outcome of replication at the site of the adduct. These experiments indicate that M₁G is indeed mutagenic. We have used a variation of this approach to establish that M₁G is repaired by nucleotide excision repair. To support and extend these in vivo studies, we conduct experiments utilizing adduct-containing duplex DNA molecules or template-primers as substrates for purified DNA polymerases or repair enzymes. These investigations provide more detailed information about the structural and functional basis for induction of mutation. Our laboratory has had a long-standing collaboration with the Stone laboratory in the Chemistry Department at Vanderbilt, which has provided precise information about the structural perturbations introduced into DNA by adducts such as M₁G.

Signal Transduction by Lipid Mediators and Lipid Peroxidation Products
A relatively new area of research in the laboratory is the definition of signal transduction pathways stimulated or interrupted by lipid mediators or lipid peroxidation products. The work on lipid mediators is focused on endocannabinoid oxygenation products of COX-2 and 15-lipoxygenase whereas the work on lipid peroxidation products is focused on malondialdehyde, 4-hydroxynonenal, and structurally related molecules. We are particularly interested in events important in controlling the growth and metastasis of cancer cells such as proliferation, migration, apoptosis and angiogenesis.

Each of the projects utilizes a range of the outstanding core facilities available at Vanderbilt (microarray, proteomics, molecular recognition, and high throughput screening) and involves stimulating collaborations with colleagues at Vanderbilt and elsewhere.

Selected Publications

Marnett LJ. Mechanisms of Cyclooxygenase-2 Inhibition and Cardiovascular Side Effects-The Plot Thickens. Cancer Prevention Research. 2009, 2 (4): 288-290.

Konkle ME, Hargrove TY, Kleshchenko YY, von Kries JP, Ridenour W, Uddin MJ, Caprioli RM, Marnett LJ, Nes WD, Villalta F, Waterman MR, Lepesheva GI. Indomethacin Amides as a Novel Molecular Scaffold for Targeting Trypanosoma cruzi Sterol 14 alpha-Demethylase. Journal of Medicinal Chemistry. 2009, 52 (9): 2846-2853.

Walters MJ, Blobaum AL, Kingsley PJ, Felts AS, Sulikowski GA, Marnett LJ. The influence of double bond geometry in the inhibition of cyclooxygenases by sulindac derivatives. Bioorganic & Medicinal Chemistry Letters. 2009, 19 (12): 3271-3274.

Uddin MJ, Marnett LJ. Synthesis of 5-and 6-Carboxy-X-rhodamines. Organic Letters. 2008, 10 (21): 4799-4801.

Bala M, Chin CN, Logan AT, Amin T, Marnett LJ, Boutaud O, Oates JA. Acetylation of prostaglandnin H-2 synthases by aspirin is inhibited by redox cycling of the peroxidase. Biochemical Pharmacology. 2008, 75 (7): 1472-1481.

Knutson CG, Skipper PL, Liberman RG, Tannenbaum SR, Marnett LJ. Monitoring in vivo metabolism and elimination of the endogenous DNA adduct, M(1)dG {3-(2-deoxy-beta-D-erythro-pentofuranosyl)pyrimido[1,2-alpha]purin-10(3H)-one}, by accelerator mass spectrometry. Chemical Research in Toxicology. 2008, 21 (6): 1290-1294.

Szekely J, Rizzo CJ, Marnett LJ. Chemical properties of oxopropenyl adducts of purine and pyrimidine nucleosides and their reactivity toward amino acid cross-link formation. Journal of the American Chemical Society. 2008, 130 (7): 2195-2201.

Turman MV, Kingsley PJ, Rouzer CA, Cravatt BF, Marnett LJ. Oxidative metabolism of a fatty acid amide hydrolase-regulated lipid, arachidonoyltaurine. Biochemistry. 2008, 47 (12): 3917-3925.

Rouzer CA, Marnett LJ. Non-redundant functions of cyclooxygenases: Oxygenation of endocannabinoids. Journal of Biological Chemistry. 2008, 283 (13): 8065-8069.

Prusakiewicz JJ, Turman MV, Vila A, Ball HL, Al-Mestarihi AH, Di Marzo V, Marnett LJ. Oxidative metabolism of lipoamino acids and vanilloids by lipoxygenases and cyclooxygenases. Archives of Biochemistry and Biophysics. 2007, 464 (2): 260-268.

Vila A, Rosengarth A, Piomelli D, Cravatt B, Marnett LJ. Hydrolysis of prostaglandin glycerol esters by the endocannabinoid-hydrolyzing enzymes, monoacylglycerol lipase and fatty acid amide hydrolase. Biochemistry. 2007, 46 (33): 9578-9585.

Wang Y, Schnetz-Boutaud NC, Saleh S, Marnett LJ, Stone MP. Bulge migration of the malondialdehdye OPdG DNA adduct when placed opposite a two-base deletion in the (CpG)(3) frameshift hotspot of the Salmonella typhimurium hisD3052 gene. Chemical Research in Toxicology. 2007, 20 (8): 1200-1210.

Joo M, Kwon M, Sadikot RT, Kingsley PJ, Marnett LJ, Blackwell TS, Peebles RS, Urade Y, Christman JW. Induction and function of lipocalin prostaglandin D synthase in host immunity. Journal of Immunology. 2007, 179 (4): 2565-2575.

Felts AS, Ji C, Stafford JB, Crews BC, Kingsley PJ, Rouzer CA, Washington MK, Subbaramaiah K, Siegel BS, Young SM, Dannenberg AJ, Marnett LJ. Desmethyl derivatives of indomethacin and sulindac as probes for cyclooxygenase-dependent biology. ACS Chemical Biology. 2007, 2 (7): 479-483.

Harman CA, Turman MV, Kozak KR, Marnett LJ, Smith WL, Garavito RM. Sturctural basis of enantioselective inhibition of cyclooxygenase-1 S-alpha-Substituted indomethacin ethanolamides. Journal of Biological Chemistry. 2007, 282 (38): 28096-28105.

Druckova A, Mernaugh RL, Ham AJL, Marnett LJ. Identification of the protein targets of the reactive metabolite of teucrin A in vivo in the rat. Chemical Research in Toxicology. 2007, 20 (10): 1393-1408.

Jacobs AT, Marnett LJ. Heat shock factor 1 attenuates 4-hydroxynonenal-mediated apoptosis - Critical role for heat shock protein 70 induction and stabilization of Bcl-X-L. Journal of Biological Chemistry. 2007, 282 (46): 33412-33420.

Knutson CG, Akingbade D, Crews BC, Voehler M, Stec DF, Marnett LJ. Metabolism in vitro and in vivo of the DNA base adduct, M(1)G. Chemical Research in Toxicology. 2007, 20 (3): 550-557.

Blobaum AL, Marnett LJ. Structural and functional basis of cyclooxygenase inhibition. Journal of Medicinal Chemistry. 2007, 50 (7): 1425-1441.

Rouzer CA, Ivanova PT, Byrne MO, Brown HA, Marnett LJ. Lipid profiling reveals glycerophospholipid remodeling in zymosan-stimulated macrophages. Biochemistry. 2007, 46 (20): 6026-6042.

Blobaum AL, Marnett LJ. Molecular determinants for the selective inhibition of cyclooxygenase-2 by lumiracoxib. Journal of Biological Chemistry. 2007, 282 (22): 16379-16390.

Lindsley CW, Weaver D, Jones C, Marnett L, Conn PJ. Preclinical drug discovery research and training at Vanderbilt. ACS Chemical Biology. 2007, 2 (1): 17-20.

Yu Y, Fan JJ, Hui YQ, Rouzer CA, Marnett LJ, Klein-Szanto AJ, FitzGerald GA, Funk CD. Targeted cyclooxygenase gene (Ptgs) exchange reveals discriminant isoform functionality. Journal of Biological Chemistry. 2007, 282 (2): 1498-1506.

Wang H, Xie H, Guo Y, Zhang H, Takahashi T, Kingsley PJ, Marnett LJ, Das SK, Cravatt BF, Dey SK. Fatty acid amide hydrolase deficiency limits early pregnancy events. Journal of Clinical Investigation. 2006, 116 (8): 2122-2131.

Jacobs AT, Marnett LJ. Inverse regulation of COX-1 and COX-2 expression in differentiating human Caco-2 colorectal carcinoma cells. Prostaglandins & Other Lipid Mediators. 2006, 79 (1-2): 176.

Specialties

• VICB
• Organic Chemistry
• Bioorganic Chemistry
• Biochemistry

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